1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/errno.h> 3 #include <linux/numa.h> 4 #include <linux/slab.h> 5 #include <linux/rculist.h> 6 #include <linux/threads.h> 7 #include <linux/preempt.h> 8 #include <linux/irqflags.h> 9 #include <linux/vmalloc.h> 10 #include <linux/mm.h> 11 #include <linux/module.h> 12 #include <linux/device-mapper.h> 13 14 #include "dm-core.h" 15 #include "dm-stats.h" 16 17 #define DM_MSG_PREFIX "stats" 18 19 static int dm_stat_need_rcu_barrier; 20 21 /* 22 * Using 64-bit values to avoid overflow (which is a 23 * problem that block/genhd.c's IO accounting has). 24 */ 25 struct dm_stat_percpu { 26 unsigned long long sectors[2]; 27 unsigned long long ios[2]; 28 unsigned long long merges[2]; 29 unsigned long long ticks[2]; 30 unsigned long long io_ticks[2]; 31 unsigned long long io_ticks_total; 32 unsigned long long time_in_queue; 33 unsigned long long *histogram; 34 }; 35 36 struct dm_stat_shared { 37 atomic_t in_flight[2]; 38 unsigned long long stamp; 39 struct dm_stat_percpu tmp; 40 }; 41 42 struct dm_stat { 43 struct list_head list_entry; 44 int id; 45 unsigned stat_flags; 46 size_t n_entries; 47 sector_t start; 48 sector_t end; 49 sector_t step; 50 unsigned n_histogram_entries; 51 unsigned long long *histogram_boundaries; 52 const char *program_id; 53 const char *aux_data; 54 struct rcu_head rcu_head; 55 size_t shared_alloc_size; 56 size_t percpu_alloc_size; 57 size_t histogram_alloc_size; 58 struct dm_stat_percpu *stat_percpu[NR_CPUS]; 59 struct dm_stat_shared stat_shared[0]; 60 }; 61 62 #define STAT_PRECISE_TIMESTAMPS 1 63 64 struct dm_stats_last_position { 65 sector_t last_sector; 66 unsigned last_rw; 67 }; 68 69 /* 70 * A typo on the command line could possibly make the kernel run out of memory 71 * and crash. To prevent the crash we account all used memory. We fail if we 72 * exhaust 1/4 of all memory or 1/2 of vmalloc space. 73 */ 74 #define DM_STATS_MEMORY_FACTOR 4 75 #define DM_STATS_VMALLOC_FACTOR 2 76 77 static DEFINE_SPINLOCK(shared_memory_lock); 78 79 static unsigned long shared_memory_amount; 80 81 static bool __check_shared_memory(size_t alloc_size) 82 { 83 size_t a; 84 85 a = shared_memory_amount + alloc_size; 86 if (a < shared_memory_amount) 87 return false; 88 if (a >> PAGE_SHIFT > totalram_pages / DM_STATS_MEMORY_FACTOR) 89 return false; 90 #ifdef CONFIG_MMU 91 if (a > (VMALLOC_END - VMALLOC_START) / DM_STATS_VMALLOC_FACTOR) 92 return false; 93 #endif 94 return true; 95 } 96 97 static bool check_shared_memory(size_t alloc_size) 98 { 99 bool ret; 100 101 spin_lock_irq(&shared_memory_lock); 102 103 ret = __check_shared_memory(alloc_size); 104 105 spin_unlock_irq(&shared_memory_lock); 106 107 return ret; 108 } 109 110 static bool claim_shared_memory(size_t alloc_size) 111 { 112 spin_lock_irq(&shared_memory_lock); 113 114 if (!__check_shared_memory(alloc_size)) { 115 spin_unlock_irq(&shared_memory_lock); 116 return false; 117 } 118 119 shared_memory_amount += alloc_size; 120 121 spin_unlock_irq(&shared_memory_lock); 122 123 return true; 124 } 125 126 static void free_shared_memory(size_t alloc_size) 127 { 128 unsigned long flags; 129 130 spin_lock_irqsave(&shared_memory_lock, flags); 131 132 if (WARN_ON_ONCE(shared_memory_amount < alloc_size)) { 133 spin_unlock_irqrestore(&shared_memory_lock, flags); 134 DMCRIT("Memory usage accounting bug."); 135 return; 136 } 137 138 shared_memory_amount -= alloc_size; 139 140 spin_unlock_irqrestore(&shared_memory_lock, flags); 141 } 142 143 static void *dm_kvzalloc(size_t alloc_size, int node) 144 { 145 void *p; 146 147 if (!claim_shared_memory(alloc_size)) 148 return NULL; 149 150 p = kvzalloc_node(alloc_size, GFP_KERNEL | __GFP_NOMEMALLOC, node); 151 if (p) 152 return p; 153 154 free_shared_memory(alloc_size); 155 156 return NULL; 157 } 158 159 static void dm_kvfree(void *ptr, size_t alloc_size) 160 { 161 if (!ptr) 162 return; 163 164 free_shared_memory(alloc_size); 165 166 kvfree(ptr); 167 } 168 169 static void dm_stat_free(struct rcu_head *head) 170 { 171 int cpu; 172 struct dm_stat *s = container_of(head, struct dm_stat, rcu_head); 173 174 kfree(s->histogram_boundaries); 175 kfree(s->program_id); 176 kfree(s->aux_data); 177 for_each_possible_cpu(cpu) { 178 dm_kvfree(s->stat_percpu[cpu][0].histogram, s->histogram_alloc_size); 179 dm_kvfree(s->stat_percpu[cpu], s->percpu_alloc_size); 180 } 181 dm_kvfree(s->stat_shared[0].tmp.histogram, s->histogram_alloc_size); 182 dm_kvfree(s, s->shared_alloc_size); 183 } 184 185 static int dm_stat_in_flight(struct dm_stat_shared *shared) 186 { 187 return atomic_read(&shared->in_flight[READ]) + 188 atomic_read(&shared->in_flight[WRITE]); 189 } 190 191 void dm_stats_init(struct dm_stats *stats) 192 { 193 int cpu; 194 struct dm_stats_last_position *last; 195 196 mutex_init(&stats->mutex); 197 INIT_LIST_HEAD(&stats->list); 198 stats->last = alloc_percpu(struct dm_stats_last_position); 199 for_each_possible_cpu(cpu) { 200 last = per_cpu_ptr(stats->last, cpu); 201 last->last_sector = (sector_t)ULLONG_MAX; 202 last->last_rw = UINT_MAX; 203 } 204 } 205 206 void dm_stats_cleanup(struct dm_stats *stats) 207 { 208 size_t ni; 209 struct dm_stat *s; 210 struct dm_stat_shared *shared; 211 212 while (!list_empty(&stats->list)) { 213 s = container_of(stats->list.next, struct dm_stat, list_entry); 214 list_del(&s->list_entry); 215 for (ni = 0; ni < s->n_entries; ni++) { 216 shared = &s->stat_shared[ni]; 217 if (WARN_ON(dm_stat_in_flight(shared))) { 218 DMCRIT("leaked in-flight counter at index %lu " 219 "(start %llu, end %llu, step %llu): reads %d, writes %d", 220 (unsigned long)ni, 221 (unsigned long long)s->start, 222 (unsigned long long)s->end, 223 (unsigned long long)s->step, 224 atomic_read(&shared->in_flight[READ]), 225 atomic_read(&shared->in_flight[WRITE])); 226 } 227 } 228 dm_stat_free(&s->rcu_head); 229 } 230 free_percpu(stats->last); 231 } 232 233 static int dm_stats_create(struct dm_stats *stats, sector_t start, sector_t end, 234 sector_t step, unsigned stat_flags, 235 unsigned n_histogram_entries, 236 unsigned long long *histogram_boundaries, 237 const char *program_id, const char *aux_data, 238 void (*suspend_callback)(struct mapped_device *), 239 void (*resume_callback)(struct mapped_device *), 240 struct mapped_device *md) 241 { 242 struct list_head *l; 243 struct dm_stat *s, *tmp_s; 244 sector_t n_entries; 245 size_t ni; 246 size_t shared_alloc_size; 247 size_t percpu_alloc_size; 248 size_t histogram_alloc_size; 249 struct dm_stat_percpu *p; 250 int cpu; 251 int ret_id; 252 int r; 253 254 if (end < start || !step) 255 return -EINVAL; 256 257 n_entries = end - start; 258 if (dm_sector_div64(n_entries, step)) 259 n_entries++; 260 261 if (n_entries != (size_t)n_entries || !(size_t)(n_entries + 1)) 262 return -EOVERFLOW; 263 264 shared_alloc_size = sizeof(struct dm_stat) + (size_t)n_entries * sizeof(struct dm_stat_shared); 265 if ((shared_alloc_size - sizeof(struct dm_stat)) / sizeof(struct dm_stat_shared) != n_entries) 266 return -EOVERFLOW; 267 268 percpu_alloc_size = (size_t)n_entries * sizeof(struct dm_stat_percpu); 269 if (percpu_alloc_size / sizeof(struct dm_stat_percpu) != n_entries) 270 return -EOVERFLOW; 271 272 histogram_alloc_size = (n_histogram_entries + 1) * (size_t)n_entries * sizeof(unsigned long long); 273 if (histogram_alloc_size / (n_histogram_entries + 1) != (size_t)n_entries * sizeof(unsigned long long)) 274 return -EOVERFLOW; 275 276 if (!check_shared_memory(shared_alloc_size + histogram_alloc_size + 277 num_possible_cpus() * (percpu_alloc_size + histogram_alloc_size))) 278 return -ENOMEM; 279 280 s = dm_kvzalloc(shared_alloc_size, NUMA_NO_NODE); 281 if (!s) 282 return -ENOMEM; 283 284 s->stat_flags = stat_flags; 285 s->n_entries = n_entries; 286 s->start = start; 287 s->end = end; 288 s->step = step; 289 s->shared_alloc_size = shared_alloc_size; 290 s->percpu_alloc_size = percpu_alloc_size; 291 s->histogram_alloc_size = histogram_alloc_size; 292 293 s->n_histogram_entries = n_histogram_entries; 294 s->histogram_boundaries = kmemdup(histogram_boundaries, 295 s->n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL); 296 if (!s->histogram_boundaries) { 297 r = -ENOMEM; 298 goto out; 299 } 300 301 s->program_id = kstrdup(program_id, GFP_KERNEL); 302 if (!s->program_id) { 303 r = -ENOMEM; 304 goto out; 305 } 306 s->aux_data = kstrdup(aux_data, GFP_KERNEL); 307 if (!s->aux_data) { 308 r = -ENOMEM; 309 goto out; 310 } 311 312 for (ni = 0; ni < n_entries; ni++) { 313 atomic_set(&s->stat_shared[ni].in_flight[READ], 0); 314 atomic_set(&s->stat_shared[ni].in_flight[WRITE], 0); 315 } 316 317 if (s->n_histogram_entries) { 318 unsigned long long *hi; 319 hi = dm_kvzalloc(s->histogram_alloc_size, NUMA_NO_NODE); 320 if (!hi) { 321 r = -ENOMEM; 322 goto out; 323 } 324 for (ni = 0; ni < n_entries; ni++) { 325 s->stat_shared[ni].tmp.histogram = hi; 326 hi += s->n_histogram_entries + 1; 327 } 328 } 329 330 for_each_possible_cpu(cpu) { 331 p = dm_kvzalloc(percpu_alloc_size, cpu_to_node(cpu)); 332 if (!p) { 333 r = -ENOMEM; 334 goto out; 335 } 336 s->stat_percpu[cpu] = p; 337 if (s->n_histogram_entries) { 338 unsigned long long *hi; 339 hi = dm_kvzalloc(s->histogram_alloc_size, cpu_to_node(cpu)); 340 if (!hi) { 341 r = -ENOMEM; 342 goto out; 343 } 344 for (ni = 0; ni < n_entries; ni++) { 345 p[ni].histogram = hi; 346 hi += s->n_histogram_entries + 1; 347 } 348 } 349 } 350 351 /* 352 * Suspend/resume to make sure there is no i/o in flight, 353 * so that newly created statistics will be exact. 354 * 355 * (note: we couldn't suspend earlier because we must not 356 * allocate memory while suspended) 357 */ 358 suspend_callback(md); 359 360 mutex_lock(&stats->mutex); 361 s->id = 0; 362 list_for_each(l, &stats->list) { 363 tmp_s = container_of(l, struct dm_stat, list_entry); 364 if (WARN_ON(tmp_s->id < s->id)) { 365 r = -EINVAL; 366 goto out_unlock_resume; 367 } 368 if (tmp_s->id > s->id) 369 break; 370 if (unlikely(s->id == INT_MAX)) { 371 r = -ENFILE; 372 goto out_unlock_resume; 373 } 374 s->id++; 375 } 376 ret_id = s->id; 377 list_add_tail_rcu(&s->list_entry, l); 378 mutex_unlock(&stats->mutex); 379 380 resume_callback(md); 381 382 return ret_id; 383 384 out_unlock_resume: 385 mutex_unlock(&stats->mutex); 386 resume_callback(md); 387 out: 388 dm_stat_free(&s->rcu_head); 389 return r; 390 } 391 392 static struct dm_stat *__dm_stats_find(struct dm_stats *stats, int id) 393 { 394 struct dm_stat *s; 395 396 list_for_each_entry(s, &stats->list, list_entry) { 397 if (s->id > id) 398 break; 399 if (s->id == id) 400 return s; 401 } 402 403 return NULL; 404 } 405 406 static int dm_stats_delete(struct dm_stats *stats, int id) 407 { 408 struct dm_stat *s; 409 int cpu; 410 411 mutex_lock(&stats->mutex); 412 413 s = __dm_stats_find(stats, id); 414 if (!s) { 415 mutex_unlock(&stats->mutex); 416 return -ENOENT; 417 } 418 419 list_del_rcu(&s->list_entry); 420 mutex_unlock(&stats->mutex); 421 422 /* 423 * vfree can't be called from RCU callback 424 */ 425 for_each_possible_cpu(cpu) 426 if (is_vmalloc_addr(s->stat_percpu) || 427 is_vmalloc_addr(s->stat_percpu[cpu][0].histogram)) 428 goto do_sync_free; 429 if (is_vmalloc_addr(s) || 430 is_vmalloc_addr(s->stat_shared[0].tmp.histogram)) { 431 do_sync_free: 432 synchronize_rcu_expedited(); 433 dm_stat_free(&s->rcu_head); 434 } else { 435 WRITE_ONCE(dm_stat_need_rcu_barrier, 1); 436 call_rcu(&s->rcu_head, dm_stat_free); 437 } 438 return 0; 439 } 440 441 static int dm_stats_list(struct dm_stats *stats, const char *program, 442 char *result, unsigned maxlen) 443 { 444 struct dm_stat *s; 445 sector_t len; 446 unsigned sz = 0; 447 448 /* 449 * Output format: 450 * <region_id>: <start_sector>+<length> <step> <program_id> <aux_data> 451 */ 452 453 mutex_lock(&stats->mutex); 454 list_for_each_entry(s, &stats->list, list_entry) { 455 if (!program || !strcmp(program, s->program_id)) { 456 len = s->end - s->start; 457 DMEMIT("%d: %llu+%llu %llu %s %s", s->id, 458 (unsigned long long)s->start, 459 (unsigned long long)len, 460 (unsigned long long)s->step, 461 s->program_id, 462 s->aux_data); 463 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) 464 DMEMIT(" precise_timestamps"); 465 if (s->n_histogram_entries) { 466 unsigned i; 467 DMEMIT(" histogram:"); 468 for (i = 0; i < s->n_histogram_entries; i++) { 469 if (i) 470 DMEMIT(","); 471 DMEMIT("%llu", s->histogram_boundaries[i]); 472 } 473 } 474 DMEMIT("\n"); 475 } 476 } 477 mutex_unlock(&stats->mutex); 478 479 return 1; 480 } 481 482 static void dm_stat_round(struct dm_stat *s, struct dm_stat_shared *shared, 483 struct dm_stat_percpu *p) 484 { 485 /* 486 * This is racy, but so is part_round_stats_single. 487 */ 488 unsigned long long now, difference; 489 unsigned in_flight_read, in_flight_write; 490 491 if (likely(!(s->stat_flags & STAT_PRECISE_TIMESTAMPS))) 492 now = jiffies; 493 else 494 now = ktime_to_ns(ktime_get()); 495 496 difference = now - shared->stamp; 497 if (!difference) 498 return; 499 500 in_flight_read = (unsigned)atomic_read(&shared->in_flight[READ]); 501 in_flight_write = (unsigned)atomic_read(&shared->in_flight[WRITE]); 502 if (in_flight_read) 503 p->io_ticks[READ] += difference; 504 if (in_flight_write) 505 p->io_ticks[WRITE] += difference; 506 if (in_flight_read + in_flight_write) { 507 p->io_ticks_total += difference; 508 p->time_in_queue += (in_flight_read + in_flight_write) * difference; 509 } 510 shared->stamp = now; 511 } 512 513 static void dm_stat_for_entry(struct dm_stat *s, size_t entry, 514 int idx, sector_t len, 515 struct dm_stats_aux *stats_aux, bool end, 516 unsigned long duration_jiffies) 517 { 518 struct dm_stat_shared *shared = &s->stat_shared[entry]; 519 struct dm_stat_percpu *p; 520 521 /* 522 * For strict correctness we should use local_irq_save/restore 523 * instead of preempt_disable/enable. 524 * 525 * preempt_disable/enable is racy if the driver finishes bios 526 * from non-interrupt context as well as from interrupt context 527 * or from more different interrupts. 528 * 529 * On 64-bit architectures the race only results in not counting some 530 * events, so it is acceptable. On 32-bit architectures the race could 531 * cause the counter going off by 2^32, so we need to do proper locking 532 * there. 533 * 534 * part_stat_lock()/part_stat_unlock() have this race too. 535 */ 536 #if BITS_PER_LONG == 32 537 unsigned long flags; 538 local_irq_save(flags); 539 #else 540 preempt_disable(); 541 #endif 542 p = &s->stat_percpu[smp_processor_id()][entry]; 543 544 if (!end) { 545 dm_stat_round(s, shared, p); 546 atomic_inc(&shared->in_flight[idx]); 547 } else { 548 unsigned long long duration; 549 dm_stat_round(s, shared, p); 550 atomic_dec(&shared->in_flight[idx]); 551 p->sectors[idx] += len; 552 p->ios[idx] += 1; 553 p->merges[idx] += stats_aux->merged; 554 if (!(s->stat_flags & STAT_PRECISE_TIMESTAMPS)) { 555 p->ticks[idx] += duration_jiffies; 556 duration = jiffies_to_msecs(duration_jiffies); 557 } else { 558 p->ticks[idx] += stats_aux->duration_ns; 559 duration = stats_aux->duration_ns; 560 } 561 if (s->n_histogram_entries) { 562 unsigned lo = 0, hi = s->n_histogram_entries + 1; 563 while (lo + 1 < hi) { 564 unsigned mid = (lo + hi) / 2; 565 if (s->histogram_boundaries[mid - 1] > duration) { 566 hi = mid; 567 } else { 568 lo = mid; 569 } 570 571 } 572 p->histogram[lo]++; 573 } 574 } 575 576 #if BITS_PER_LONG == 32 577 local_irq_restore(flags); 578 #else 579 preempt_enable(); 580 #endif 581 } 582 583 static void __dm_stat_bio(struct dm_stat *s, int bi_rw, 584 sector_t bi_sector, sector_t end_sector, 585 bool end, unsigned long duration_jiffies, 586 struct dm_stats_aux *stats_aux) 587 { 588 sector_t rel_sector, offset, todo, fragment_len; 589 size_t entry; 590 591 if (end_sector <= s->start || bi_sector >= s->end) 592 return; 593 if (unlikely(bi_sector < s->start)) { 594 rel_sector = 0; 595 todo = end_sector - s->start; 596 } else { 597 rel_sector = bi_sector - s->start; 598 todo = end_sector - bi_sector; 599 } 600 if (unlikely(end_sector > s->end)) 601 todo -= (end_sector - s->end); 602 603 offset = dm_sector_div64(rel_sector, s->step); 604 entry = rel_sector; 605 do { 606 if (WARN_ON_ONCE(entry >= s->n_entries)) { 607 DMCRIT("Invalid area access in region id %d", s->id); 608 return; 609 } 610 fragment_len = todo; 611 if (fragment_len > s->step - offset) 612 fragment_len = s->step - offset; 613 dm_stat_for_entry(s, entry, bi_rw, fragment_len, 614 stats_aux, end, duration_jiffies); 615 todo -= fragment_len; 616 entry++; 617 offset = 0; 618 } while (unlikely(todo != 0)); 619 } 620 621 void dm_stats_account_io(struct dm_stats *stats, unsigned long bi_rw, 622 sector_t bi_sector, unsigned bi_sectors, bool end, 623 unsigned long duration_jiffies, 624 struct dm_stats_aux *stats_aux) 625 { 626 struct dm_stat *s; 627 sector_t end_sector; 628 struct dm_stats_last_position *last; 629 bool got_precise_time; 630 631 if (unlikely(!bi_sectors)) 632 return; 633 634 end_sector = bi_sector + bi_sectors; 635 636 if (!end) { 637 /* 638 * A race condition can at worst result in the merged flag being 639 * misrepresented, so we don't have to disable preemption here. 640 */ 641 last = raw_cpu_ptr(stats->last); 642 stats_aux->merged = 643 (bi_sector == (READ_ONCE(last->last_sector) && 644 ((bi_rw == WRITE) == 645 (READ_ONCE(last->last_rw) == WRITE)) 646 )); 647 WRITE_ONCE(last->last_sector, end_sector); 648 WRITE_ONCE(last->last_rw, bi_rw); 649 } 650 651 rcu_read_lock(); 652 653 got_precise_time = false; 654 list_for_each_entry_rcu(s, &stats->list, list_entry) { 655 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS && !got_precise_time) { 656 if (!end) 657 stats_aux->duration_ns = ktime_to_ns(ktime_get()); 658 else 659 stats_aux->duration_ns = ktime_to_ns(ktime_get()) - stats_aux->duration_ns; 660 got_precise_time = true; 661 } 662 __dm_stat_bio(s, bi_rw, bi_sector, end_sector, end, duration_jiffies, stats_aux); 663 } 664 665 rcu_read_unlock(); 666 } 667 668 static void __dm_stat_init_temporary_percpu_totals(struct dm_stat_shared *shared, 669 struct dm_stat *s, size_t x) 670 { 671 int cpu; 672 struct dm_stat_percpu *p; 673 674 local_irq_disable(); 675 p = &s->stat_percpu[smp_processor_id()][x]; 676 dm_stat_round(s, shared, p); 677 local_irq_enable(); 678 679 shared->tmp.sectors[READ] = 0; 680 shared->tmp.sectors[WRITE] = 0; 681 shared->tmp.ios[READ] = 0; 682 shared->tmp.ios[WRITE] = 0; 683 shared->tmp.merges[READ] = 0; 684 shared->tmp.merges[WRITE] = 0; 685 shared->tmp.ticks[READ] = 0; 686 shared->tmp.ticks[WRITE] = 0; 687 shared->tmp.io_ticks[READ] = 0; 688 shared->tmp.io_ticks[WRITE] = 0; 689 shared->tmp.io_ticks_total = 0; 690 shared->tmp.time_in_queue = 0; 691 692 if (s->n_histogram_entries) 693 memset(shared->tmp.histogram, 0, (s->n_histogram_entries + 1) * sizeof(unsigned long long)); 694 695 for_each_possible_cpu(cpu) { 696 p = &s->stat_percpu[cpu][x]; 697 shared->tmp.sectors[READ] += READ_ONCE(p->sectors[READ]); 698 shared->tmp.sectors[WRITE] += READ_ONCE(p->sectors[WRITE]); 699 shared->tmp.ios[READ] += READ_ONCE(p->ios[READ]); 700 shared->tmp.ios[WRITE] += READ_ONCE(p->ios[WRITE]); 701 shared->tmp.merges[READ] += READ_ONCE(p->merges[READ]); 702 shared->tmp.merges[WRITE] += READ_ONCE(p->merges[WRITE]); 703 shared->tmp.ticks[READ] += READ_ONCE(p->ticks[READ]); 704 shared->tmp.ticks[WRITE] += READ_ONCE(p->ticks[WRITE]); 705 shared->tmp.io_ticks[READ] += READ_ONCE(p->io_ticks[READ]); 706 shared->tmp.io_ticks[WRITE] += READ_ONCE(p->io_ticks[WRITE]); 707 shared->tmp.io_ticks_total += READ_ONCE(p->io_ticks_total); 708 shared->tmp.time_in_queue += READ_ONCE(p->time_in_queue); 709 if (s->n_histogram_entries) { 710 unsigned i; 711 for (i = 0; i < s->n_histogram_entries + 1; i++) 712 shared->tmp.histogram[i] += READ_ONCE(p->histogram[i]); 713 } 714 } 715 } 716 717 static void __dm_stat_clear(struct dm_stat *s, size_t idx_start, size_t idx_end, 718 bool init_tmp_percpu_totals) 719 { 720 size_t x; 721 struct dm_stat_shared *shared; 722 struct dm_stat_percpu *p; 723 724 for (x = idx_start; x < idx_end; x++) { 725 shared = &s->stat_shared[x]; 726 if (init_tmp_percpu_totals) 727 __dm_stat_init_temporary_percpu_totals(shared, s, x); 728 local_irq_disable(); 729 p = &s->stat_percpu[smp_processor_id()][x]; 730 p->sectors[READ] -= shared->tmp.sectors[READ]; 731 p->sectors[WRITE] -= shared->tmp.sectors[WRITE]; 732 p->ios[READ] -= shared->tmp.ios[READ]; 733 p->ios[WRITE] -= shared->tmp.ios[WRITE]; 734 p->merges[READ] -= shared->tmp.merges[READ]; 735 p->merges[WRITE] -= shared->tmp.merges[WRITE]; 736 p->ticks[READ] -= shared->tmp.ticks[READ]; 737 p->ticks[WRITE] -= shared->tmp.ticks[WRITE]; 738 p->io_ticks[READ] -= shared->tmp.io_ticks[READ]; 739 p->io_ticks[WRITE] -= shared->tmp.io_ticks[WRITE]; 740 p->io_ticks_total -= shared->tmp.io_ticks_total; 741 p->time_in_queue -= shared->tmp.time_in_queue; 742 local_irq_enable(); 743 if (s->n_histogram_entries) { 744 unsigned i; 745 for (i = 0; i < s->n_histogram_entries + 1; i++) { 746 local_irq_disable(); 747 p = &s->stat_percpu[smp_processor_id()][x]; 748 p->histogram[i] -= shared->tmp.histogram[i]; 749 local_irq_enable(); 750 } 751 } 752 } 753 } 754 755 static int dm_stats_clear(struct dm_stats *stats, int id) 756 { 757 struct dm_stat *s; 758 759 mutex_lock(&stats->mutex); 760 761 s = __dm_stats_find(stats, id); 762 if (!s) { 763 mutex_unlock(&stats->mutex); 764 return -ENOENT; 765 } 766 767 __dm_stat_clear(s, 0, s->n_entries, true); 768 769 mutex_unlock(&stats->mutex); 770 771 return 1; 772 } 773 774 /* 775 * This is like jiffies_to_msec, but works for 64-bit values. 776 */ 777 static unsigned long long dm_jiffies_to_msec64(struct dm_stat *s, unsigned long long j) 778 { 779 unsigned long long result; 780 unsigned mult; 781 782 if (s->stat_flags & STAT_PRECISE_TIMESTAMPS) 783 return j; 784 785 result = 0; 786 if (j) 787 result = jiffies_to_msecs(j & 0x3fffff); 788 if (j >= 1 << 22) { 789 mult = jiffies_to_msecs(1 << 22); 790 result += (unsigned long long)mult * (unsigned long long)jiffies_to_msecs((j >> 22) & 0x3fffff); 791 } 792 if (j >= 1ULL << 44) 793 result += (unsigned long long)mult * (unsigned long long)mult * (unsigned long long)jiffies_to_msecs(j >> 44); 794 795 return result; 796 } 797 798 static int dm_stats_print(struct dm_stats *stats, int id, 799 size_t idx_start, size_t idx_len, 800 bool clear, char *result, unsigned maxlen) 801 { 802 unsigned sz = 0; 803 struct dm_stat *s; 804 size_t x; 805 sector_t start, end, step; 806 size_t idx_end; 807 struct dm_stat_shared *shared; 808 809 /* 810 * Output format: 811 * <start_sector>+<length> counters 812 */ 813 814 mutex_lock(&stats->mutex); 815 816 s = __dm_stats_find(stats, id); 817 if (!s) { 818 mutex_unlock(&stats->mutex); 819 return -ENOENT; 820 } 821 822 idx_end = idx_start + idx_len; 823 if (idx_end < idx_start || 824 idx_end > s->n_entries) 825 idx_end = s->n_entries; 826 827 if (idx_start > idx_end) 828 idx_start = idx_end; 829 830 step = s->step; 831 start = s->start + (step * idx_start); 832 833 for (x = idx_start; x < idx_end; x++, start = end) { 834 shared = &s->stat_shared[x]; 835 end = start + step; 836 if (unlikely(end > s->end)) 837 end = s->end; 838 839 __dm_stat_init_temporary_percpu_totals(shared, s, x); 840 841 DMEMIT("%llu+%llu %llu %llu %llu %llu %llu %llu %llu %llu %d %llu %llu %llu %llu", 842 (unsigned long long)start, 843 (unsigned long long)step, 844 shared->tmp.ios[READ], 845 shared->tmp.merges[READ], 846 shared->tmp.sectors[READ], 847 dm_jiffies_to_msec64(s, shared->tmp.ticks[READ]), 848 shared->tmp.ios[WRITE], 849 shared->tmp.merges[WRITE], 850 shared->tmp.sectors[WRITE], 851 dm_jiffies_to_msec64(s, shared->tmp.ticks[WRITE]), 852 dm_stat_in_flight(shared), 853 dm_jiffies_to_msec64(s, shared->tmp.io_ticks_total), 854 dm_jiffies_to_msec64(s, shared->tmp.time_in_queue), 855 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[READ]), 856 dm_jiffies_to_msec64(s, shared->tmp.io_ticks[WRITE])); 857 if (s->n_histogram_entries) { 858 unsigned i; 859 for (i = 0; i < s->n_histogram_entries + 1; i++) { 860 DMEMIT("%s%llu", !i ? " " : ":", shared->tmp.histogram[i]); 861 } 862 } 863 DMEMIT("\n"); 864 865 if (unlikely(sz + 1 >= maxlen)) 866 goto buffer_overflow; 867 } 868 869 if (clear) 870 __dm_stat_clear(s, idx_start, idx_end, false); 871 872 buffer_overflow: 873 mutex_unlock(&stats->mutex); 874 875 return 1; 876 } 877 878 static int dm_stats_set_aux(struct dm_stats *stats, int id, const char *aux_data) 879 { 880 struct dm_stat *s; 881 const char *new_aux_data; 882 883 mutex_lock(&stats->mutex); 884 885 s = __dm_stats_find(stats, id); 886 if (!s) { 887 mutex_unlock(&stats->mutex); 888 return -ENOENT; 889 } 890 891 new_aux_data = kstrdup(aux_data, GFP_KERNEL); 892 if (!new_aux_data) { 893 mutex_unlock(&stats->mutex); 894 return -ENOMEM; 895 } 896 897 kfree(s->aux_data); 898 s->aux_data = new_aux_data; 899 900 mutex_unlock(&stats->mutex); 901 902 return 0; 903 } 904 905 static int parse_histogram(const char *h, unsigned *n_histogram_entries, 906 unsigned long long **histogram_boundaries) 907 { 908 const char *q; 909 unsigned n; 910 unsigned long long last; 911 912 *n_histogram_entries = 1; 913 for (q = h; *q; q++) 914 if (*q == ',') 915 (*n_histogram_entries)++; 916 917 *histogram_boundaries = kmalloc(*n_histogram_entries * sizeof(unsigned long long), GFP_KERNEL); 918 if (!*histogram_boundaries) 919 return -ENOMEM; 920 921 n = 0; 922 last = 0; 923 while (1) { 924 unsigned long long hi; 925 int s; 926 char ch; 927 s = sscanf(h, "%llu%c", &hi, &ch); 928 if (!s || (s == 2 && ch != ',')) 929 return -EINVAL; 930 if (hi <= last) 931 return -EINVAL; 932 last = hi; 933 (*histogram_boundaries)[n] = hi; 934 if (s == 1) 935 return 0; 936 h = strchr(h, ',') + 1; 937 n++; 938 } 939 } 940 941 static int message_stats_create(struct mapped_device *md, 942 unsigned argc, char **argv, 943 char *result, unsigned maxlen) 944 { 945 int r; 946 int id; 947 char dummy; 948 unsigned long long start, end, len, step; 949 unsigned divisor; 950 const char *program_id, *aux_data; 951 unsigned stat_flags = 0; 952 953 unsigned n_histogram_entries = 0; 954 unsigned long long *histogram_boundaries = NULL; 955 956 struct dm_arg_set as, as_backup; 957 const char *a; 958 unsigned feature_args; 959 960 /* 961 * Input format: 962 * <range> <step> [<extra_parameters> <parameters>] [<program_id> [<aux_data>]] 963 */ 964 965 if (argc < 3) 966 goto ret_einval; 967 968 as.argc = argc; 969 as.argv = argv; 970 dm_consume_args(&as, 1); 971 972 a = dm_shift_arg(&as); 973 if (!strcmp(a, "-")) { 974 start = 0; 975 len = dm_get_size(md); 976 if (!len) 977 len = 1; 978 } else if (sscanf(a, "%llu+%llu%c", &start, &len, &dummy) != 2 || 979 start != (sector_t)start || len != (sector_t)len) 980 goto ret_einval; 981 982 end = start + len; 983 if (start >= end) 984 goto ret_einval; 985 986 a = dm_shift_arg(&as); 987 if (sscanf(a, "/%u%c", &divisor, &dummy) == 1) { 988 if (!divisor) 989 return -EINVAL; 990 step = end - start; 991 if (do_div(step, divisor)) 992 step++; 993 if (!step) 994 step = 1; 995 } else if (sscanf(a, "%llu%c", &step, &dummy) != 1 || 996 step != (sector_t)step || !step) 997 goto ret_einval; 998 999 as_backup = as; 1000 a = dm_shift_arg(&as); 1001 if (a && sscanf(a, "%u%c", &feature_args, &dummy) == 1) { 1002 while (feature_args--) { 1003 a = dm_shift_arg(&as); 1004 if (!a) 1005 goto ret_einval; 1006 if (!strcasecmp(a, "precise_timestamps")) 1007 stat_flags |= STAT_PRECISE_TIMESTAMPS; 1008 else if (!strncasecmp(a, "histogram:", 10)) { 1009 if (n_histogram_entries) 1010 goto ret_einval; 1011 if ((r = parse_histogram(a + 10, &n_histogram_entries, &histogram_boundaries))) 1012 goto ret; 1013 } else 1014 goto ret_einval; 1015 } 1016 } else { 1017 as = as_backup; 1018 } 1019 1020 program_id = "-"; 1021 aux_data = "-"; 1022 1023 a = dm_shift_arg(&as); 1024 if (a) 1025 program_id = a; 1026 1027 a = dm_shift_arg(&as); 1028 if (a) 1029 aux_data = a; 1030 1031 if (as.argc) 1032 goto ret_einval; 1033 1034 /* 1035 * If a buffer overflow happens after we created the region, 1036 * it's too late (the userspace would retry with a larger 1037 * buffer, but the region id that caused the overflow is already 1038 * leaked). So we must detect buffer overflow in advance. 1039 */ 1040 snprintf(result, maxlen, "%d", INT_MAX); 1041 if (dm_message_test_buffer_overflow(result, maxlen)) { 1042 r = 1; 1043 goto ret; 1044 } 1045 1046 id = dm_stats_create(dm_get_stats(md), start, end, step, stat_flags, 1047 n_histogram_entries, histogram_boundaries, program_id, aux_data, 1048 dm_internal_suspend_fast, dm_internal_resume_fast, md); 1049 if (id < 0) { 1050 r = id; 1051 goto ret; 1052 } 1053 1054 snprintf(result, maxlen, "%d", id); 1055 1056 r = 1; 1057 goto ret; 1058 1059 ret_einval: 1060 r = -EINVAL; 1061 ret: 1062 kfree(histogram_boundaries); 1063 return r; 1064 } 1065 1066 static int message_stats_delete(struct mapped_device *md, 1067 unsigned argc, char **argv) 1068 { 1069 int id; 1070 char dummy; 1071 1072 if (argc != 2) 1073 return -EINVAL; 1074 1075 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1076 return -EINVAL; 1077 1078 return dm_stats_delete(dm_get_stats(md), id); 1079 } 1080 1081 static int message_stats_clear(struct mapped_device *md, 1082 unsigned argc, char **argv) 1083 { 1084 int id; 1085 char dummy; 1086 1087 if (argc != 2) 1088 return -EINVAL; 1089 1090 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1091 return -EINVAL; 1092 1093 return dm_stats_clear(dm_get_stats(md), id); 1094 } 1095 1096 static int message_stats_list(struct mapped_device *md, 1097 unsigned argc, char **argv, 1098 char *result, unsigned maxlen) 1099 { 1100 int r; 1101 const char *program = NULL; 1102 1103 if (argc < 1 || argc > 2) 1104 return -EINVAL; 1105 1106 if (argc > 1) { 1107 program = kstrdup(argv[1], GFP_KERNEL); 1108 if (!program) 1109 return -ENOMEM; 1110 } 1111 1112 r = dm_stats_list(dm_get_stats(md), program, result, maxlen); 1113 1114 kfree(program); 1115 1116 return r; 1117 } 1118 1119 static int message_stats_print(struct mapped_device *md, 1120 unsigned argc, char **argv, bool clear, 1121 char *result, unsigned maxlen) 1122 { 1123 int id; 1124 char dummy; 1125 unsigned long idx_start = 0, idx_len = ULONG_MAX; 1126 1127 if (argc != 2 && argc != 4) 1128 return -EINVAL; 1129 1130 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1131 return -EINVAL; 1132 1133 if (argc > 3) { 1134 if (strcmp(argv[2], "-") && 1135 sscanf(argv[2], "%lu%c", &idx_start, &dummy) != 1) 1136 return -EINVAL; 1137 if (strcmp(argv[3], "-") && 1138 sscanf(argv[3], "%lu%c", &idx_len, &dummy) != 1) 1139 return -EINVAL; 1140 } 1141 1142 return dm_stats_print(dm_get_stats(md), id, idx_start, idx_len, clear, 1143 result, maxlen); 1144 } 1145 1146 static int message_stats_set_aux(struct mapped_device *md, 1147 unsigned argc, char **argv) 1148 { 1149 int id; 1150 char dummy; 1151 1152 if (argc != 3) 1153 return -EINVAL; 1154 1155 if (sscanf(argv[1], "%d%c", &id, &dummy) != 1 || id < 0) 1156 return -EINVAL; 1157 1158 return dm_stats_set_aux(dm_get_stats(md), id, argv[2]); 1159 } 1160 1161 int dm_stats_message(struct mapped_device *md, unsigned argc, char **argv, 1162 char *result, unsigned maxlen) 1163 { 1164 int r; 1165 1166 /* All messages here must start with '@' */ 1167 if (!strcasecmp(argv[0], "@stats_create")) 1168 r = message_stats_create(md, argc, argv, result, maxlen); 1169 else if (!strcasecmp(argv[0], "@stats_delete")) 1170 r = message_stats_delete(md, argc, argv); 1171 else if (!strcasecmp(argv[0], "@stats_clear")) 1172 r = message_stats_clear(md, argc, argv); 1173 else if (!strcasecmp(argv[0], "@stats_list")) 1174 r = message_stats_list(md, argc, argv, result, maxlen); 1175 else if (!strcasecmp(argv[0], "@stats_print")) 1176 r = message_stats_print(md, argc, argv, false, result, maxlen); 1177 else if (!strcasecmp(argv[0], "@stats_print_clear")) 1178 r = message_stats_print(md, argc, argv, true, result, maxlen); 1179 else if (!strcasecmp(argv[0], "@stats_set_aux")) 1180 r = message_stats_set_aux(md, argc, argv); 1181 else 1182 return 2; /* this wasn't a stats message */ 1183 1184 if (r == -EINVAL) 1185 DMWARN("Invalid parameters for message %s", argv[0]); 1186 1187 return r; 1188 } 1189 1190 int __init dm_statistics_init(void) 1191 { 1192 shared_memory_amount = 0; 1193 dm_stat_need_rcu_barrier = 0; 1194 return 0; 1195 } 1196 1197 void dm_statistics_exit(void) 1198 { 1199 if (dm_stat_need_rcu_barrier) 1200 rcu_barrier(); 1201 if (WARN_ON(shared_memory_amount)) 1202 DMCRIT("shared_memory_amount leaked: %lu", shared_memory_amount); 1203 } 1204 1205 module_param_named(stats_current_allocated_bytes, shared_memory_amount, ulong, S_IRUGO); 1206 MODULE_PARM_DESC(stats_current_allocated_bytes, "Memory currently used by statistics"); 1207